This invention relates generally to crankcase ventilation valves and more particularly to a freeze-resistant positive crankcase ventilation valve.
Crankcase ventilation valves are provided to vent blow-by gases from the crankcase of an internal combustion engine and return such gases to the intake manifold. Typically, such valves have a pintle for metering the gases which closes when the engine is shut down. Often, in cold weather, especially in very cold climates, the pintle freezes in the closed position. Then when the engine is restarted, the pintle remains frozen shut and does not re-open, or opening is delayed until the engine warms up to produce enough heat to unfreeze or thaw the pintle. Until the pintle is unfrozen, the blow-by gases cannot be vented from the crankcase. To avoid such delay, electric heating devices have been employed, at considerable expense.
In accordance with this invention, a crossbar extends across the path of the pintle so that when the engine shuts down the pintle does not close all the way against the usual valve seat but rather closes against the crossbar. In that way, the valve is open even when the engine is not running. The crossbar is a relatively narrow member having a reduced area of contact with the pintle so that any freezing of moisture between the crossbar and the pintle is quickly broken away when the engine is turned on and the pintle resumes its normal operation. Even if there is a slight delay in the unfreezing of the pintle, the blow-by gases can still be vented because the pintle never fully closes and the valve remains open at all times.
Further in accordance with the invention, the ventilation valve has an elongated valve casing having an inlet adapted to communicate with the crankcase and an outlet adapted to communicate with an engine intake manifold for the flow of crankcase gases drawn from the crankcase through the valve casing by the engine intake manifold when the engine is running. The metering pintle reciprocates in the casing. The crossbar extends across the casing adjacent to but spaced outwardly of the inlet. A spring presses the pintle against the crossbar when the engine is not running. However, because the crossbar is spaced from the inlet, the valve is open even when the engine is not running. The pintle is moved away from the crossbar against the pressure of the spring by the intake manifold vacuum when the engine is running to meter the flow of the crankcase gases. Preferably, the crossbar is a roll pin.
One object of this invention is to provide a freeze-resistant positive crankcase ventilation valve having the foregoing features and capabilities.
Another object is to provide a freeze-resistant positive crankcase ventilation valve which is composed of a relatively few simple parts and is inexpensive to manufacture and assemble.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.